jpegtran has always given me good results in this area. It strips all metadata, not just EXIF, and it also losslessly optimises the compression to further reduce the filesize. Obviously this latter operation exacts a fair toll on the CPU. It can also do other wacky stuff like lossless scaling, cropping and rotation.

http://jpegclub.org/jpegtran/

    jpegtran -optimize -copy none -o outfile.jpg image.jpg

EDIT: recursive in-place optimization and stripping of all jpegs under current dir:

    find . -iname \*.jp*g -exec jpegtran -optimize -copy none -verbose -outfile {} {} \;